Engine and pump unit



June 1, 1948. MacKENDRlCK 2,442,468

ENGINE AND PUMP UNIT Filed Jan. 29, 1946 2 Sheets-Sheet 1 an Li E June i, 1948. J. N. MacKENDRICK 2,442,463

ENGINE m ruur UNIT Filed Jan. 29, 1946 2 Sheets-Sheet 2 I INVENTOR. k

Patented June 1, 1948 ENGINE AND P'Ulllll? UNIT John N. MacKendrick, Olean, N. Y., assignor to Clark Bros. 00., 1110., Olean, N. Y., a corporation of New York Application January 29, 1946, Serial No. 643,987

3 Claims. 1

My invention relates to combined units of a reciprocating pump'or pumps and an internal combustion engine of the type that requires a pump or pumps for scavenging purposes. More particularly it relates to the nature of the scavenging pump or pumps and to the interconnections and relations between the various pumps and between them and the engine portion of the structure.

For conciseness and in order to distinguish readily between the scavenging pump 01' pumps which are auxiliaries of the engine, and the reciprocating pump or pumps which it is the primary purpose of the engine to drive, I call the latter a compressor or compressors, it being understood however that the invention is not limited to gas compressors. Accordingly it will be understood that the word compressor in this specification and in the claims includes a reciprocating pump for pumping or compressing any kind of material whatsoever.

Speaking generally the invention tends to minimize the unbalanced or unneutralized forces in the engine-compressor unit, and thus to minimize its weight and its tendency to vibrate, while at the same time providing or permitting a well proportioned and conveniently shaped structure.

It contemplates scavenging pumps of the reciprocating type, and, speaking generally, the placement of a scavenging pump at the opposite side of the crankshaft from a compressor, two engine cylinders for each scavenging pump and compressor, and the engine cylinders disposed substantially at right angles to the pump and compressor cylinders and at about the same position along the crankshaft; and also such a connection of the engine, compressor and scavenging pump pistons to the crankshaft that the pistons of two opposing compressor and scavenging pumps operate substantially 180 out of phase with each other (both moving toward the crankshaft together and both moving away from it together), and the two engine pistons operate substantially 180 out of phase with each other and each substantially 90 out of phase with the compressor and scavenging pump pistons (i. e. each engine piston being at one end of its travel when the compressor and scavenging pistons are at midpoints of their respective reciprocations). These angular relations can be, and preferably are, secured by providing the crankshaft with two cranks and crank pins at the scavenging and compressor cylinder pair (and at each pair if there are two or more such pairs), placed 180 apart, and coupling one engine piston and the scavenging pump piston to one of those crank pins and coupling the other engine piston and the piston of the compressor to the other crank pin. In the case of larger engines (1. e. engines having more than two cylinders), scavenging pumps and compressors can be distributed along the crankshaft in such opposed pairs, for example one pair of scavenging and compressor cylinders for each pair of engine cylinders, and the relations between each such pair of engine cylinders and their pistons and their related scavenging pump and compressor cylinders and pistons can be as described above. As between pairs of en gine pistons of the larger engines, these can be so connected to the crankshaft that power is applied to the shaft at about as constant rate as possible-for example with a four cylinder two cycle engine, each engine piston may be so connected to the crankshaft as to apply power to the shaft or one-fourth of a rotation of the shaft behind another piston.

For the best results, speaking generally, the weight of the reciprocating system of each member of an opposed pair (e. g. the piston, piston rod, cross-head if any, etc., of a compressor), should equal or approximate the weight of the reciprocating system of the opposing member (e. g. the piston, piston rod, cross-head if any, etc., of the opposing scavenging pump). If necessary to se cure this result, weight may be added to a reciprocating system. Also to the same end or for some other reason, it may be desirable in some instances to employ a smaller number of scavenging pumps than compressors, thus permitting the scavenging pumps to be larger than otherwise and the compressors smaller for a given total capacity for the unit. For example, two scavenging pumps and four compressors may be used with a six cylinder engine; each of the two scavenging pumps may be disposed opposite a compressor and the two remaining compressors disposed at opposite sides of the shaft from each other; or the two scavenging pumps can be opposed to each other and the compressors opposed to each other in pairs.

It is to be understood that whenever herein and in the claims hereafter I refer to a crank, I intend to include therewith eccentrics and any other devices that may be used generally similarly to transfer power between a reciprocating piston and a rotating shaft.

A preferred form of my invention as applied to an engine-compressor unit having-a two-cycle four-cylinder engine is illustrated in the accompanying drawings. These drawings are wholly tic as will be evident. Fig.1 illustrates the relative positions of the engine, scavenging and compressor cylinders in vertical end section.

tons reciprocate.

As will be evident the drawings are intended to show only the relative positions of the various cylinders and the connections of their Pistons to the crankshaft. The particular constructions of these various parts and the manner in which they are supported, as well as the accessory parts and the form of the accessory parts that may be used with the parts illustrated, are immaterial to the present invention, and such constructions and forms may be used as the designer may wish.

Briefly the four cylinders I, 2, 3 and l or the engine (which may be of the two-cycle Diesel type) are arranged substantially in line parallel with and, say, above the crankshaft I. The crankshaft is provided with four cranks B, I, 8 and 9. The connecting rods I4 of the pistons is of the respective cylinders I to l of the engine are connected to these cranks 8 to 8 respectively. As will be recognized from the drawing, the adjacent cranks 8 and l are displaced 180 from each other. Likewise the two cranks 8 and 9 are displaced 180 from each other. However the pair of cranks 6 and 1 is displaced 90 from the pair of cranks 8 and 8 as will be understood from Figs. 2 and 3. Accordingly the beginnings of the power strokes of the various engine pistons I5 follow each other at the ends of equal periods of time and the various cylinders of the engine deliver power to the crankshaft 5 at substantially equi-angular points in the rotations of the crankshaft.

The cylinders of two reciprocating compressors It or I1 are disposed substantially at right angles to the plane of the engine cylinders I to I; the axes of these compressor cylinders substantially intersect the axis of the crankshaft within the areas of rotation of the cranks and 8 respectively, as will be seen from Fig. 2. As before indicated, each compressor may be or any convenient form of the reciprocating type. In the present instance they are double acting as indicated by the diagrammatic representations of ports I2 in Fig. 1, i. e. each is constructed to compress and discharge gas (air or other gas) at both ends of its cylinder. Especially in view of the double acting nature of the compressors, each has a crosshead It to which its piston rod I8 is connected, while a connecting rod I8 connects each cross head to a crank of the engine-compressor unit. Specifically, preferably, the compressor pistons are connected to alternate cranks, e. g. the piston of compressor cylinder I 8 is connected to the crank 6, and the piston of compressor I1 is connected to the crank 8.

At the opposite side ofthe engine cylinders I to 4 and the crankshaft 5 from the compressors Ii and I1, and respectively substantially opposite the respective compressors I6 and I1, and with the axes of their cylinders in substantially the same plane as the axes of thecompressor cylinders, are located reciprocating scavenging pumps 4 flandllwhichamthroughpipcsltmpply scavengingairtothemanifoldl'l whichinturn supplies sca fl g air to the various engine cylindersitolinsubstantiallyacustomarymanner. The axes of-these scaven ing pump cylinderssubstantiallyintersecttheaxisotthe crankshaft within the areas of rotation or the cranks I and 8 respectively, Fig. 2. Since the respectively opposing compressors I8 and I! are double acting, preferably these two scavenging pumps 24 and 28 are double acting also. Their piston rods 28 are connected to cross-heads 28 and the latter are connected to cracks of the engine-compressor unit by the connecting rods 38. Specifically, the piston or scaven g ylinder 24 is connected to crank I and the piston of cylinder 25 is connected to crank 8, so that each pair of oppodng pump and compressor cylinders is served by adjacent cranks oi a crank pair located adjacent the respective opposing pair of cylinders. It will be understood of course that the invention is not limited to double-action compressing.

The pistons II of the engine portion of the structure drive the crankshaft 8 of the unit of course, and the crankshaft reciprocates the pump and compressor pistons as will be understood. The order in which the various pistons illustrated operate can be seen from Figs. 1, 2 and 3, but is shown specifically in Fig. 4. In this Fig. 4 the horizontal lines represent the passage of time and periods corresponding to individual rotations of the crankshaft are indicated. The angular lines and legends indicate, respectively, the

directions in which the various pistons or the engine, scavenging pumps and compressors are moving at every instance throughout two complete shaft rotations. For example, at each instant when the piston I I of the engine cylinder I is in its upper position and about to start downward (on a power stroke in this instance), the piston of the associated scavenging pump 24 is in its mldposition and is moving toward the right, the piston of the associated compressor II is in its mid-pontion and is moving toward the left, and at the same moment the piston II of the associated engine cylinder 2 is about to start upwards (on a compression stroke in this instance). Atthe same instant also thepiston of engine cylinder 3 is in the middle of an upward stroke, the piston of scavenging pump 25 is about to start toward the right, the piston of engine cylinder 4 is in the middle of a down stroke, and the piston of compressor I1 is about to start toward the left.. With this description the positions of the various reciprocating systems and their directions of movement at other moments will be understood from Fig. 4.

Assuming that the weights of the reciprocat ing systems of the four engine cylinders I to 4 are about equal and that the arms of the cranks t, I. 8 and 8 are of eq l lengths (or that these and the power delivered by the various cylinders are properly correlated as will be understood), it is evident that the reactions at the various engine cylinders offset and neutralize each other about as well as conveniently possible in the form of engine illustrated, and resultant couples are dependent on the distances between connecting rods. In addition however, since the cranks 6 and I are or equal lengths and the weight of the reciprocating system of the scavenging pump :4

equals the weight of the reciprocating system of the compressor It (or if these weights and the lengths of the crank arms are correlated as will be understood), the reactions of the compressor it are substantially offset and neutralized by the reactions of the pump 24. Also the same is true with respect to the compressor I1 and its companion scavenging pump 25. The resultant couples are dependent on the relatively short distance between the connecting rods of 24 and I6, and between the connecting rods of 25 and 11. Any unbalance from the various reactions of the structure that may remain can be further neutralized of course in manners that are known in engine practice. However, the self-balance and self-neutralization of reactions of the parts as explained, minimizes the need for such extraneous balancing mechanisms.

If in any instance the cranks serving two opposing members, such as the pump 24 and compressor l6, are not of equal lengths, this may be compensated for by a proper proportioning of the weights of their reciprocating systems as suggested before and as will be understood.

The minimization of unbalanced and unneutralized forces minimizes the tendency of the structure as a whole, and its parts, to vibrate of course, and thereby permits the structure as a whole and its various parts to be made of minimum weight.

It will be understood of course that my invention is not limited to the details of construction and operation shown in the accompanying drawings and described above except as appears hereafter in the claims.

I claim:

1. In a combined engine and compressor unit, an internal combustion engine having at least two power cylinders, a piston in each 01' said two cylinders, and a crankshaft having two cranks substantially 180 apart, the said two cylinders being disposed in line lengthwise of the crankshaft, and one of said pistons being connected to one of said cranks, and the other being connected to the other of said cranks, a scavenging pump for said engine having a cylinder disposed at about right angles to said power cylinders, the axis of said scavenging pump cylinder intersecting the axis of the crankshaft within the area of rotation of one or said cranks, a compressor having a cylinder also disposed at about right angles to said power cylinders, but at the opposite side of the crankshaft from said scaven ing pump cylinder, the axis of said compressor cylinder intersecting the axis of the crankshaft within the area of rotation of the other of said cranks, a piston in said scavenging cylinder connected to the adjacent crank, and a piston in said compressor cylinder connected to the crank which is respectfully adJacent the compressor cylinder.

2. In a combined engine and compressor unit, an internal combustion engine having a plural.- ity of pairs of cylinders, pistons therein and a crankshaft, said crankshaft having substantially at each of said pairs of cylinders two cranks disposed substantially 180 apart, such pairs of cranks being disposed substantially equi-angularly around the axis of the crankshaft, and said pistons being connected to said crankshaft to apply power thereto at substantially equl-angularly spaced positions in the rotations of the shaft, a plurality of cylinders for scavenging pumps and compressors, each of said scavenging and compressor cylinders being disposed at substantially the opposite sides of said shaft from another of said scavenging and compressor cylinders and each such two cylinders being adjacent one of said pairs of cranks, and a piston in each of said scavenging and compressor cylinders, one piston or each of said two respectively opposing scavenging and compressor cylinders being connected to one of the two respectively adjacent cranks and the other piston of the respective two cylinders being connected to the other of the respectively adjacent two cranks.

3. In a combined engine and compressor unit, a crankshaft having a plurality of pairs of cranks, the two cranks of each .such pair being disposed substantially apart andthe pairs being disposed substantially equi-angularly around the axis of the crankshaft, a plurality of scavenging pump and compressor cylinders disposed with their axes in substantially the same plane, with each of said scavengin and compressor cylinders at the opposite side of the crankshaft from another thereof, and with each such two scavenging and compressor cylinders disposed adjacent one of said pairs of cranks, a piston in each of the scavenging and compressor cylinders, .one piston of each such two cylinders being connected to one crank of the respectively adjacent pair of cranks and the piston of the other of the two cylinders of each pair being connected to the other crank of the respectivel adjacent pair of cranks, a plurality of internal combustion engine cylinders disposed at one side of said plane of the scavenging and compressor cylinders, and pistons in said engine cylinders connected to said cranks.

JOHN N. MAcKENDRICK.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS 

